<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>js字符串学习</title>
    <script src="index.js"></script>
    <link rel="stylesheet" href="index.css"/>
</head>
<body>
<button type="button" onclick="fuc1()">字符串测试1</button>
<br><br>
<button type="button" onclick="fuc2()">字符串测试2</button>
<br><br>
<button type="button" onclick="fuc3()">字符串变为大写字母</button>
<br><br>
<button type="button" onclick="fuc4()">字符串变为小写字母</button>
<br><br>
<button type="button" onclick="fuc5()">搜索指定字符串出现的位置</button>
<br><br>

<button type="button" onclick="fuc6()">返回指定索引区间的子串</button>
<br><br>
</body>
</html>